Heart failure (HF), also termed congestive HF (CHF) is a cardiac condition that occurs when a problem with the structure or function of the heart impairs its ability to supply sufficient blood flow to meet the body's needs. It can cause a large variety of symptoms, particularly shortness of breath (SOB) at rest or during exertion and/or fatigue, signs of fluid retention such as pulmonary congestion or ankle swelling, and objective evidence of an abnormality of the structure or function of the heart at rest. However, some patients can be completely symptom free and asymptomatic structural or functional abnormalities of the heart are considered as precursors of symptomatic heart failure and are associated with high mortality.
Heart failure is a common disease: more than 2% of the U.S. population, or almost 5 million people, are affected and 30 to 40% of patients die from heart failure within 1 year after receiving the diagnosis.
Heart failure is often undiagnosed due to a lack of a universally agreed definition and challenges in definitive diagnosis, particularly in the early stage.
With appropriate therapy, heart failure can be managed in the majority of patients, but it is a potentially life threatening condition, and progressive disease is associated with an overall annual mortality rate of 10%. In addition, it is the leading cause of hospitalization in people older than 65 years. As a consequence, the management of heart failure consumes 1-2% of total health-care expenditure in European countries.
Chronic HF is a long-term condition developing over months and years with a usually stable treated symptomatology. This condition is associated with heart undergoing adaptive responses that, however, can be deleterious in the long-term and lead to a worsening condition. Acute HF (AHF) is a term used to describe exacerbated or decompensated heart failure, referring to episodes in which a patient can be characterized as having a change in heart failure signs and symptoms resulting in a need for urgent therapy or hospitalization. AHF develops rapidly during hours or days and can be immediately life threatening because the heart does not have time to undergo compensatory adaptations. Chronic HF may also decompensate which most commonly result from an intercurrent illness (such as pneumonia), myocardial infarction, arrhythmias, uncontrolled hypertension, or a patient's failure to maintain a fluid restriction, diet or medication.
The possibility of predicting adverse events at presentation of the patient is important, since early recognition of risk is a prerequisite for initiating measures helping to prevent the development of adverse events. In this regard, several attempts have been made in order to find markers that can provide accurate prognostic information.
Clinically, several biomarkers have received great attention as predictors of prognosis in HF, being natriuretic peptides the most extensively used, but others, such as ST2 and high-sensitivity troponin T, have also shown promising results, doing so in an additive fashion to natriuretic peptides. When measuring the level of the biomarker, it is also very important that clinicians understand confounding factors that may weaken or undermine the accuracy of the test. A classic example of this is how body-mass index or impaired renal function influences blood concentrations of natriuretic peptides in HF.
Therefore, in spite of the efforts made, there is still the need of further prognostic markers which can provide useful information in the managing of HF disease.